Heat shield arrangements for a rolling mill

ABSTRACT

A heat shield arrangement for strip material employs insulating panels of thin-walled composite construction. The panels include an upper series displaceable upwardly by power actuation means to avoid damage by buckled or lifting material. Protective members projecting below the upper panels are associated with sensing means to actuate the raising of the upper panels and can have a limited displacement before the raising of the upper panels is actuated. The power actuation means can themselves act on the sensing means to determine the minimum force from the material that causes raising of said panels. Control means displace the panels in response to the sensed transverse temperature profile to maintain the profile more uniform and some of the panels may have heating means for this purpose.

This is a division of Ser. No. 351,148, filed Feb. 22, 1982, now U.S.Pat. No. 4,463,585, which was itself a divisional of Ser. No. 91,752,filed Nov. 6, 1979, now U.S. Pat. No. 4,343,168, which itself was acontinuation-in-part of Ser. No. 902,560 filed May 3, 1978, nowabandoned.

BACKGROUND OF THE INVENTION

This invention relates to heat shields and it is concerned particularly,but not exclusively, with heat shields for use in metal processing.

In steel mill processing whether of billets, strip or sections, themetallurgical qualities of finished product are closely related to theaccurate control of temperature of the material during the hot rollingprocess. For example, a modern hot strip mill producing steel coil isseveral hundred meters long and typically, steel slabs or billets may bereduced from 25 cms thickness to 0.2 cms using several roughing millstands and five or more finishing mill stands. During the rollingprocess considerable heat losses occur so that the slabs have to beheated initially well in excess of the temperature requirement at theend of the process, but a particular problem has been that the heatlosses from slabs passing along the mill depend upon the time taken. Ifthe slabs are delayed, excessive heat losses occur and the steel stripdoes not have its required rolling temperatures, so that it may have tobe downgraded or even scrapped. In many long modern rolling mills thedelay of one length of strip at the finishing end has an effect on theseveral lengths of material which are simultaneously at variouspreceding stages of rolling. Thus with more stringent qualityspecifications it is becoming more important to reduce the rate of heatloss from the material during transport between stands.

There is an added difficulty in this because during the final reductionstages the back end of the strip takes longer to pass through thefinishing mills and so there is a temperature "run-down" along the steelstrip due to the cumulative time delay along the length of the strip.The effect of temperature "run-down" is to some extent ameliorated byaccelerating the finishing mills during the rolling of each individualslab or strip, but nevertheless it remains a problem.

Attempts have been made in the past to reduce the heat loss from the topsurface of a hot strip during transport from the roughing mills to thefinishing mills. Because radiation is a major source of heat loss at thetemperatures involved (around 1060° C.) aluminium reflectors have beenfixed over the path of the hot strip to reduce temperature "run-down".However maintenance problems limit the usefulness of reflectors whichbecome inefficient as soon as they become dirty, and in addition, thealuminium reflectors which have been used for their high reflectivityand relatively low cost can reach their melting temperature if theirreflectivity decreases.

It has been proposed (UK Pat. No. 1 040 420) to use heat-insulating orreflecting panels as heat shields that present to the hot material aface formed by a thin plate of stainless steel backed by a core ofthermal insulation, so that the plate forming the hot face of the panelis preheated to a luminous temperature close to that of the materialbeing processed. In this arrangement, however, the panel could be easilydamaged if there is a malfunction that causes material being processedto strike the panel, for example if the material is bent or if it liftsas it runs along its path. A mishap of this kind can easily occur in asteel rolling mill in which the steel stock is often travelling at veryhigh speeds.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided aheat shield arrangement for hot material being processed in ahot-rolling mill, e.g. for metal strip (e.g. a slab or sheet ) or forrolled metal sections, the arrangement comprising a series of heatinsulating panels above the path of the material being processed, thepanels each having a heat-insulating core and a cover plate forming oroverlying a main face of the panel being adapted to act as a hot facepresented to the material being processed and to radiate heat back tothe material, the series of panels being provided with displacementmeans for displacing them on their supports upwardly away from the pathof the material and sensing means being provided adjacent the materialpath responsive to upward distortion or lifting of the material and toactuate thereby control means that initiate operation of saiddisplacement means to lift the panels away from the material to protectthem against damage.

It is thus possible to provide contact elements projecting downwardly inthe region of the cover plates of the upper group of panels to below thelevel of the cover plates, said contact elements being of a relativerobust nature compared with the panel cover plates and acting as sensingmeans for operating control means that actuate said panel displacementmeans, whereby if the material lifts and strikes the contact means thedisplacement means are immediately actuated to lift the panels away fromthe hot strip material.

Although raising the upper panels clear of its material will protectthose panels from damage, there is the disadvantage that each time thishappens the sheet material will itself be adversely affected by theuncontrolled cooling that occurs when the upper panels are raised. Therewill be many instances when the rolling process has been interruptedunnecessarily, with consequent increase of costs and delay, because thelifting of the strip material would not have caused damage to thepanels.

According to another aspect of the present invention, there is provideda heat shield arrangement for a heated length of strip material (e.g. aslab or sheet) comprising heat-insulating panels arranged adjacent to atravel path for the material and including a series of upper panelsextending over said path, displacement means comprising power actuationmeans for raising said upper panels away from said path being actuableby sensing means responsive to lifting or upward deformation of thestrip, said power actuation means influencing the sensing means todetermine the magnitude of the upward force from the strip at which thesensing means responds, whereby the panels are maintained in operativelowered positions in normal operating conditions until said determinedforce is exceeded.

Preferably, protective bumper or fender elements project below the upperpanels. These elements may be fixed relative to the upper panels butpreferably they are carried by mounting means that permit somedisplacement relative to the panels. The sensing means may similarly befixed relative to the upper panels but preferably comprise elements alsomounted in a relatively displaceable manner, advantageously on saidprotective element mounting means.

The invention makes it possible to provide a relatively restrictedvertical spacing between the upper and lower panels without disturbingthat spacing except in case of need. Problems can arise, however,because although during rolling the main extent of a slab or strip willusually be relatively flat, its ends can be turned-up (i.e. curvedupwards or downwards) to a certain degree because of the forces appliedto each end portion as it passes unsupported through a set of rolls, andthe effective height of the material may be increased thereby to manytimes the material thickness. This effect is particularly marked when astrip is rolled in a semi-continuous mill having reversing roughing rollstands through which the initial slab is passed forwards and backwardsrepeatedly to reduce its thickness, but in a continuous mill the leadingend of the strip will also be deformed in a similar way.

According to another aspect of the invention, there is provided a heatshield arrangement with heat-insulating panels arranged adjacent to atravel path at least an intermediate region longitudinally of said pathwhere upper and lower series of panels are disposed with a limitedvertical spacing between them to form a travel path of restrictedheight, and wherein at an entry region of the arrangement an increasedheight passage is provided for the introduction of a turned-up stripmaterial, said entry passage decreasing in height to lead into thelimited vertical spacing of said intermediate region.

This measure can be employed with particular advantage in combinationwith the displacement means operable in dependence on the force of thelifted material, as aforesaid, since the entry region may offersufficient resistance to reduce the turn-up of the leading end of thematerial and so help to minimise the vertical spacing between the upperand lower insulating panel in the intermediate part of the heat shieldarrangement. The employment of an increased height entry section is,however, also of value if the aforesaid displacement means are notprovided.

It is possible for the entry region, especially if relatively short, tocomprise a relatively robust bar or frame structure with littleheat-insulating effect if any, but it will be preferred, particularly ifit is required to provide a relatively large maximum height entry, thatat least a part of the entry region is composed of upper and lowerheat-insulating panels the vertical distance between which panels isprogressively reduced along the length of the material path towards saidintermediate region.

In an arrangement in which the main or intermediate path of the channelpath has a relatively uniform insulating effect due to the closeness ofthe upper and lower panels, the benefit of this may be partly lost wherethe panels must be more widely spaced apart, for example at an increasedheight entry region. In such cases, to obtain the desired degree ofuniformity of heat insulation it may be preferred to provide panels atthe sides of the strip travel path, with heating elements disposed on orwithin at least some of said side panels. In this way it is possible tocounteract the greater heat loss from the edges of the material due tothe additional surface area, and especially at the ends of the heatshield arrangement where in addition to any increased spacing of theupper and lower panels, the panels may themselves not be close to theheated material temperature.

In any event, the panels are preferably so arranged that they provide anenclosure that substantially completely surrounds the material path.Alternatively, it may be sufficient to arrange that there issubstantially no straight-line path for heat radiation from the strippast the panels transverse to the travel path of the strip.

In the arrangement disclosed in UK Pat. No. 1 040 420, theheat-insulating panels are disposed in series over a rolling mill delaytable, so as to reduce the loss of heat from hot sheet material on thetable, and a pyrometer immediately in front of each panel is able toactuate displacement of its panel transversely away from the table.Thus, when the strip advances onto the delay table each insulating panelwill be moved to its operative position over the strip if the pyrometersenses a strip temperature significantly less than a preset value, andif the temperature rises above the preset value the panels are displacedlaterally clear of the table and the strip.

This arrangement, however, is only of limited value because it reliesupon the temperature of the strip being sufficiently uniform over theregion of each panel for effective control of the panel temperature tobe obtained by the positioning of the heat-insulating panel in one ofits two alternative positions. There can in fact be significant localtemperature gradients, and it has been found that there may inparticular be significant temperature differences across the width of asheet of hot material--so that there is likely to be a substantiallyhigher rate of cooling of the outer lateral margins of the sheet ascompared with its central region.

According to another aspect of the present invention, a heat shieldarrangement is provided comprising a series of heat-insulating panelsmounted above a path for the hot material, the panels each having aheat-insulating core and a cover plate forming or overlying a main faceof each panel being adapted to act as a hot face presented to thematerial being processed and to radiate heat back to the material,characterised in that the panels of the series are arranged in groups oftwo or more panels disposed side-by-side across the lateral extent ofthe path of the material, and means are connected to said plurality ofpanels for displacing the panels with respect to each other for varyingtheir heat-insulating effect on a central region of the hot materialrelative to the lateral margins thereof, at least one array oftemperature sensors being laterally spaced across the material path, andcontrol means actuated by said sensors being connected to saiddisplacement means in order to control the temperature and/or thetransverse temperature profile of the material being processed inaccordance with predetermined values.

Said displacement of the panels may take place by movement of thelaterally opposed panels towards and away from each other, maintainingtheir height above the material path, or it can involve tilting of thepanels so that they are raised relative to the central region of thematerial path and therefore have a lesser effect there, but preferablythe displacement means are adpated to provide both these motions aloneor in combination.

A heat shield arrangement according to the invention preferably also hasheat-insulating panels disposed below the material path. These panelsalso may be arranged to be displaceable for varying the heat-insulatingeffect across the width of the material, e.g. by providing means formoving them laterally towards and away from each other.

On a conventional strip mill delay table, the sheet material path isdefined by a series of rollers on which the material is supported.According to a preferred feature of the invention, said rollers compriseupper smaller diameter rollers upon which the material rests, and lowerlarger diameter rollers that support the upper rollers. In this way, itis possible to increase the proportion of the lower face of the materialpath that is shielded by the lower series of heat-insulating panels,since these panels can overlap the larger rollers to extend close to theupper, smaller diameter rollers.

There is a further advantage arising from the use of the smallerdiameter upper rollers in that the heat transfer by conduction throughthese will be less than for the larger diameter rollers of aconventional rolling mill table. This loss can be still further reducedby limiting the contact area between the upper and lower rollers, inparticular by arranging that the upper rollers are only in contact witha plurality of axially spaced larger diameter portions formed on thelower rollers.

Preferably, the upper series of panels are mounted on support meansprovided with a raising mechanism which allows them to be raised to gainaccess to the conveying path, and the raising mechanism may be arrangedto operate automatically to protect the panels should there by amalfunction that causes the material being processed to lift and strikethe panels.

The control of the temperature of material being processed by varyingthe heat shielding effect transversely across the material is notappropriate in some instances, for example in processing narrowcross-section materials such as bars and rolled sections. In theseinstances, according to another aspect of the invention, there isprovided a heat shield arrangement comprising heat-insulating panelsdisposed along a path of the material being processed, the panels eachhaving a heat-insulating core and a cover plate forming or overlying theface of each panel being adapted to act as a hot face presented to thematerial being processed and to radiate heat back to the panel,characterised in that the panels form a tubular enclosure to surroundall sides of the material path with the upper and lower regions of saidconduit being provided by respective upper and lower panels, and atleast some of the panels being mounted on displaceable support means toopen the tubular enclosure.

Conveniently, contact means for the material being processed areprovided for operation of the displacement means of the displaceablymounted panels in order to lift said panels away to avoid damage bymaterial that is distorted or that has lifted, as already discussed.

In a preferred construction for the performance of the invention, eachpanel comprises a core of fibrous ceramic material providing aheat-insulating layer and enclosed in a protective casing, the coverplate forming or overlying a main face of said casing and being capableof relative thermal expansion with respect to the casing. If the coverplate is made relatively thin to have a low thermal capacity, at least apart of its area may be provided with dimples, corrugations or otherlocally contoured formations to increase the heat emissivity of itssurface and such contouring may also be arranged to contribute to thestrength of the cover plate and its ability to withstand thermalstresses, as well as to allow a measure of independent thermal expansionby flexure.

The casing may comprise a peripheral housing that supports the coverplate in a manner that permits relative thermal expansion of the coverlayer, and the opposite main face of the panel forming its cold face maysimilarly be provided with a cover plate mounted in a manner permittingrelative thermal expansion, so that thermal stresses on the casing arekept to a minimum.

Preferably, the casing provides a substantially dust-tight enclosure forthe insulating core and venting apertures may be arranged in the casingfor the escape of air and steam from within, the apertures beingprovided with valves for preventing or limiting a return flow throughthem.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more particularly described by way of example,with reference to the accompanying drawings, wherein:

FIG. 1 is a longitudinal vertical section of a portion of the stripconveying path in a hot strip rolling mill showing upper and lowerpanels according to the invention used in a heat shield arrangement,

FIG. 2 is a perspective view of a part of a transfer conveyor of themill showing only the upper panels in place,

FIG. 3 is a graph illustrating temperature run-down of a slab in a hotstrip mill and the influence on this of a heat shield arrangementaccording to the invention,

FIG. 4 is a transverse cross-section of a heat shield arrangement,analogous in many respects to the embodiment of the invention shown inFIG. 2, but incorporating adjustment means for the panels,

FIG. 5 is a schematic illustration of the control means for thearrangement of FIG. 4,

FIG. 6 is a transverse cross-section of a protective device for thearrangement of FIGS. 4 and 5,

FIG. 7 is a transverse cross-section of a further form of heat shieldarrangment according to the invention,

FIGS. 8 and 9 are schematic illustrations of alternative heat-insulatingpanels for the arrangement of FIG. 7,

FIGS. 10 and 11 illustrate details of a modified front plateconstruction for a panel according to the invention,

FIG. 12 is a longitudinal section of a heat shield arrangementillustrating a feature that can be employed in the arrangements of FIG.2 or FIG. 4,

FIGS. 13 and 14 illustrate in mutually transverse sections a modifiedroller construction that can also be employed in the arrangements ofFIG. 2 or FIG. 4,

FIG. 15 is an isometric view of a heat shield arrangement having upperpanel displacement means according to the invention,

FIG. 16 is a fluid control diagram for the panel displacement means ofthe arrangement in FIG. 15,

FIG. 17 is a schematic side view of a heat shield arrangement accordingto the invention between successive roll stands in a continuous rollingmill,

FIG. 18 shows to a larger scale a detail of the entry end of the heatshield arrangement of FIG. 17,

FIG. 19 is a schematic side view of a heat shield arrangement accordingto the invention between successive roll stands in a semi-continuousrolling mill,

FIG. 20 is a sectional view on the line X--X in FIG. 19,

FIG. 21 is a schematic illustration to explain the manner in whichdifferent heat loss rates occur over the width of a hot strip, and

FIG. 22 is a diagrammatic sectional view of a heat shield arrangementhaving side insulating panels with heating means according to theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1 of the drawings, a hot strip mill delay table isshown with a hot steel slab or strip 1 resting on rollers 2 and with lowthermal mass insulation panels according to the invention disposed aboveand below the strip.

The upper panel comprises a casing containing a two-layer core ofheat-insulating material consisting of high temperature ceramic fibreboard insulation 4 adjoining a bottom cover plate 3 forming the hot faceof the panel, the insulation 4 being backed by lower temperatureinsulating board 5. The cover plate 3 is formed by a thin sheet oftemperature resistant material, e.g. stainless steel, which material canbe made either heat reflecting or adsorbing. The cover plate rests uponheat-resistant angle-section frame 7 of the casing, which allows freethermal expansion of the plate, and slots 31 in the frame also allow itsrelative thermal expansion. The top of the panel is sealed by a topplate 10 to which is fixed a mounting lug 11.

In use, as the hot strip 1 enters under the panel heat radiated from thestrip will impinge on the cover plate. Initially the front end of thestrip will cool at almost the rate it would achieve in free air whilethe cover plate is cool. If the plate is thin--for example, less than1/50th of the thickness of the hot strip 1--then its temperature willquickly rise to closely approach the strip temperature without asignificant drop in strip temperature, and as heat loss into the panelis minimised by the thermally insulating core and the panel almostimmediately begins to re-radiate heat and approach thermal equilibriumwith the strip.

The total effective emissivity of the cover plate of the re-radiatingpanel is increased by substantial corrugating or dimpling or like localcontouring 6 of its surface, and since the cover plate is preferablyvery thin such contouring can serve to strengthen the plate and allowlocal flexing to facilitate relaxation of thermal stresses set up byrapid heating and cooling of the plate.

The cover plate is held from above against the horizontal flanges of theframe 7 by leaf springs 8 to help provide a seal between the plate andthe frame and so minimise the intrusion of dirt and steam into theceramic fibre core. Vents 9 can also be provided in the side walls ofthe mounting frame 7 to facilitate the escape of steam if, as duringperiods of inactivity, water is adsorbed by the core and is subsequentlyvaporised by the heating that occurs when the panel begins to be usedagain. One-way flap valves 30 on the vents 9 help to prevent the ingressof steam from the surroundings. It should be noted that if the coverplate is very thin, extra retaining clips 13 may be required to hold itagainst the ceramic fibre material of the core.

It will be clear that almost half the heat radiated by the strip is fromits lower surface. The problems presented in placing a panel under thestrip are greater than for the top panel and in general a modifiedconstruction will be required. The lower panel shown in FIG. 1 issupported on the table base plate 15 and can rest thereon eitherdirectly or through brackets 16. The cover plate 17 forming the hot faceof the lower panel has local contouring like the plate 3 but forms anintegral part of an outer casing of welded construction with stainlesssteel side walls 18 and base 19 as below the strip greater protection isneeded against the ingress of foreign matter. The contouring ispreferably in the form of a series of parallel corrugations arrangedparticularly to accommodate thermal expansion of the hot face relativeto the remainder of the panel, but because the cover plate is restrainedat its edges, the casing is made relatively narrow in the direction ofthe corrugations, e.g. some half the length transverse thereto. Thecorrugations also increase the effective emissivity of the hot face, asmentioned above, and strengthen the relatively thin material.

The base of the casing has one or more corrugations 20 to allowdifferential thermal expansion and the panel is filled with a core ofhigher and lower temperature insulating ceramic fibre panels 21, 22respectively, similar to the upper panel core. Small steam vents 23 areprovided in the base of the panel to allow venting of trapped water andthese are normally closed by one-way flap valves 30.

A number of lower panels are disposed side-by-side across the width ofthe strip and not only reduce the heat loss from the bottom of thestrip, but by extending close to the opposed sides of successive rollersof the delay table they also reduce the thermal load on the rollersthereby improving their operating life and reducing the amount of watercooling required.

The effect of a series of such upper and lower panels as a heat shieldin a rolling mill can best be understood by reference to FIG. 3, whichshows the temperature of a strip or slab at entry to the roll train of amill after it has passed along a delay table. Curve A shows how thetemperature of the strip, as sensed at the mill entry, runs down becauseof the increasing heat losses that have occurred at points progressivelyfurther back along the length of the strip due to the increasing delaybefore entry as dictated by the travel speed of the strip in the rolls.The initial temperature of the strip would be, say 2012° F. and whilethe front end temperature loss might be some 100° F. at mill entry(point F), further back along the strip the material arrives at the millwith a progressively lower temperature. Curve B shows how the heatshield arrangement of panels according to the invention gives a similartemperature fall at the front end of the strip, while the panels arestill cool, but they almost immediately radiate heat to reduce thetemperature fall and very quickly approach the initial temperature ofthe strip and can reverse the temperature profile for the rear end ofthe strip, so as to give a more uniform temperature at roll entry.

In a sufficiently long run, the rear end temperature of strip can ofcourse approach the initial strip temperature but in general the form ofthe temperature distribution at points along the strip length at theirentry to the mill can be controlled by choice of the storage andconductivity characteristics of the hot faces of the panels and the heatinsulating cores. It is even possible to incorporate heating means inthe panels adjacent their hot faces to give a more uniform exittemperature, but usually this would only be required for material havinga relatively low thermal mass, such as bars and sections.

As already stated, the cover plates can be heat-reflecting but ingeneral it will be found convenient to make them black to suit the dirtyenvironmental conditions and in this case they can operate better toimprove the temperature distribution in the common condition of a stripwith a higher temperature leading end in the manner shown in FIG. 3, orsimilarly where there is some time lag in the passage of the trailingend to a roll stand.

The mounting of the lower panels presents no problems but the top panelsrequire to be mounted so that they can be readily lifted from over thehot strip, e.g. for maintenance or to allow the removal of the strip inthe event of a long stoppage or to prevent damage to the panel if thereis a buckled or bent strip. FIG. 2 illustrates a mounting means suitablefor strip mill applications in which upper panels 32 are suspended overthe tables in pairs by their top plates 10 and mounting lugs 11 frombooms 12, although for narrow mills one panel width will be sufficientto span the roller table whereas on wide mills as many as four panelsside-by-side may be required. The panels are arranged in a row or rowsextending along the strip-conveying direction to make up the requiredheat shield area. It will be understood that the smaller width of thelower panels dictated by thermal expansion considerations in thisparticular use will result in the provision of a larger number of panelsthan the upper panels to cover the same width.

The booms 12 are mounted as cantilevers from shafts 24 on externalfloor-mounted frames at one side of the mill the shafts being supportedin rotary bearing blocks 25 to be able to pivot the booms throughsubstantially 90° between the horizontal position shown and a raisedvertical or near vertical position. Columns 26 carrying the bearingblocks are positioned so as to provide access to the roller drive motors(not shown) of the mill. The panels and booms are counterbalanced on theshafts by weights 27 and the movement of the panels is obtained bymotors 28, e.g. hydraulically operated, which are designed to givepositive drive both when raising and lowering the panels.

Operator controls (not shown) are provided for the motors 28 to allowthe panels to be raised and lowered for maintenance or access to themill. To prevent damage to the panels during operation, e.g. if there isa bent or buckled strip in the mill, a skid bumper bar or fender bar 14is fitted to certain of the panels or to the boom structure so that thebent strip will contact the bar to push the panels upwards. Preferably,the skid bumper bars are connected to pressure switches 29 whichactivate the raising movement of the motors 28 in such an eventuality,so that the panels are lifted independently of the force on them.

In FIGS. 4 to 6 there is shown a further development of the invention inthe example of steel strip rolling mill similar in many respects to thatshown in FIG. 2, but in which the heat shield panels can be adjusted inposition to achieve a more uniform temperature distribution in the hotmaterial.

Upper panels 40 are mounted on cantilever arms 41 over the conveyor forthe steel strip 1, so that as in FIG. 2 the panels are able to cover theentire upper face of the strip. In this embodiment not only are thecantilever arm supports of the panels displaceable to move the panelstowards and away from the strip, but the panels themselves aredisplaceable on the arms to regulate their effect on the strip.

For this purpose the panels may be conveniently arranged in pairs withthe central bumper bar 14 independently mounted between them. The panelsare supported by transverse rails 42 that are secured below thecantilever arms and are suspended from rollers 42a running on the railsso that they can be displaced laterally towards and away from each otherby rams 43, as indicated by the arrows A in FIG. 4. Each rail is pivotedat its inner end 44 and connected by rams 45 to the arm 41, so that byoperation of the rams the rails can be tilted about their pivots, and inparticular can be so tilted as to raise the laterally outer edges of thepanels as shown in outline in FIG. 4. The lower heat shield panels 46below the strip path are also mounted through rollers 47a on rails 47,which in this instance are fixed, so as to be movable laterally inwardsand outwards by rams 48 in the same manner as the upper panels.

The movements of the different rams during the operation of thearrangement to control the temperature of a steel strip travelling alongthe conveyor path is governed by a control unit 60 (FIG. 5) receivingsignals from an array of temperature sensors 61 disposed across thewidth of the strip. It is unnecessary to illustrate the detailedconstruction of the unit 60, since the principles of control equipmentdesign by which these signals are utilised to give the outputs indicatedbelow are well understood and are fully within the knowledge of a personskilled in the art. If the sensors indicate that the temperature at theedges of the strip is too high, the rams 45 between the cantilever armsand the upper rails 42 can be operated to tilt the outer edges of theupper panels upwards, the angle being adjusted to suit the required heatloss rate. If, on the other hand, the temperature at the centre of thestrip is too high the panels 40 and/or 46 can be traversed on theirrails so as to leave a gap at the centre, both above and below thestrip, to allow increased radiation from that region. The extent of theopening movement and the number of panels opened along the length of theconveyor path can both be adjusted to suit the extent of the temperaurecorrection required.

It is also possible to lift the cantilever arms 41, with the panels 40,this serving both as a means of temperature control for the strip and asa means of protection of the panels against damage from a bent orbuckled strip. For this purpose, as may be more clearly seen from FIG.4. each arm 41 is mounted on a fixed frame 50 through a normallyhorizontal shorter link 51 pivoted at 52 to the lower end of the arm anda longer link 53 pivoted at 54 intermediate the length of the arm andnormally lying parallel to the cranked end portion of the arm. The arm41 is displaced by a ram 55 attached to one end 56 to the frame 50 andits other end 57 being connected to the longer link 53. The mechanismoperates, when the ram 55 is extended, to produce a magnified pivotingmovement of the arm 41, as shown in FIG. 4, the stroke of the ram beingset so that the panels can be raised to a nearly vertical position,leaving clear access to the roller table.

As already indicated, the ram 55 can be operated by the automaticcontrol means to regulate the temperature of the material. This can bedone when it is required to lower the temperature of the strip as awhole rather than alter the temperature distribution, and normally itwill be sufficient for only a small length of the total length of theupper series of heat shields to be lifted away for this purpose. Thenumber of panels so raised will determine the cooling effect obtained.The rams 55 may also be automatically operated if a bent or buckledstrip is in the mill. The bumper bars 14 provide initial protection inthis eventuality, but they also can be provided with pressure-sensitiveswitches so that as the strip bears against them, the rams 46 areactuated and the upper panels are immediately raised clear of the strip,independently of whether they have actually been contacted by thedeformed strip.

It will be understood that the control unit may comprise means forreadily adjusting the set points or required temperature limits to suitdifferent materials being processed, and there may be a number of arraysof temperature sensors at different stations along the length of thestrip conveyor path, either operating upon the same control unit oroperating upon separate control units for individual stations of theconveyor path.

The bumper bar 14 may be used in a similar manner to that described withreference to FIG. 2, to raise or actuate raising of the upper panelswhen there is a risk of damage from buckled or bent stock. Additionallyor alternatively, there may be a bent stock detector 62 (FIGS. 5 and 6)disposed over the conveyor upstream of the panels to indicate theapproach of raised parts of the strip that might damage the panels. Thedetector support arm 63 may have a simple pivot mounting 64, controlledby a ram 65, to swing the detector clear of the conveyor when required,but it may alternatively have the same form of displacement mechanism asthe arms 41. It should be understood, moreover, that such a detector mayalso be employed in the first-described arrangement in which the panelsare fixedly mounted on their support.

The invention is not restricted to installations in which the heatedmaterial is in strip form, and FIGS. 7 to 9 illustrate the applicationof the invention to control the temperature of bar or profiled sectionstock moving along a conveyor path.

Mounted on a fixed frame 71 are drive rollers 72 for the stock 73, shownhere as a square section bar, driven by one or more motors 74. Theconveyor path runs perpendicular to the plane of the figure. Mountings76 pivotable about an axis 77 parallel to the conveyor path carryupwardly projecting side support rollers 78 for the stock and lower heatshield panels 80 of the composite construction already described.Together with upper U-form panels 81 of similar construction these lowerpanels 80 form a tubular enclosure for the stock. The upper panels 81are supported on pivot mountings 82 that allow them to be swung upwardsto the broken-line position by rams 83, clear of the conveyor and thestock on it. When the upper panels have been swung away in this manner,the side support rollers 78 can be pivoted downwards to give free accessto the stock, in particular to allow bent or damaged stock to be removedmore easily. The pivoting of the mountings 76 for the lower panels 80allows them to be tilted when the installation is being serviced toshake off any accumulation of mill scale or other foreign matter.

Because the top panel has a cross-sectional profile that increases itsstiffness as compared with the flat panels so far described, it can bemade considerably longer: it may have flat faces 84 or axialcorrugations 85 can be provided to stiffen the inner cover plate, as hasalready been described. This inner cover plate is allowed some freedomto expand axially and laterally and is retained in place by lipped edges86 of the panel casing and heat-resistant ties 87 passing through theinner core of insulating material. A bumper bar 88 projects through thetop panels to protect them from being damaged by out-of-shape material.As already described, the bar can be provided with impact sensors 89arranged to trigger the operation of the lifting rams 83 for raising thetop panels.

The cross-sectional profile of the panels can be varied, for example, tosuit a particular cross-section profile material, as is exemplified inFIGS. 8 and 9. In FIG. 8, the bottom panel 91 also has a U-form profileincreasing its stiffness and the radiussing of the cover plates at theinner corners 92 of the panels can improve the uniformity of thetemperature of the stock passing through the arrangement. The corners ofrectangular stock or even of the outer edges of the flanges of theI-section shown will normally radiate heat more freely and so coolfaster, but the increased insulation of the radiussed corners of thepanels has an opposite and therefore compensating effect. A similareffect can be obtained with the configuration shown in FIG. 9, whereboth panels 93 have a semi-circular cross-section.

In some circumstances it may be required not only to conserve the heatin the material being processed but also to apply further heating. Forexample, this might be necessary if the material is to be held at aconstant temperature. It is possible then to provide heating means in oron the insulation panels themselves, as is illustrated in FIGS. 10 and11. These show a multi-layer cover plate, with a front plate 101 formingthe hot face of the panel, a first electrically insulating layer 102, anelectrical strip heating element 103 capable of operating at atemperature of 1100° C. or more, a second insulating layer 104, and aback plate 105 that like the front plate is suitable for use at hightemperatures. The layers are secured together by hollow rivets 106 thatmay also serve to receive suspension ties 107 for the panel, althoughpanels with cover plates of this construction are suitable for mountingboth above and below the material being shielded. To maintain thematerial temperature, the element 103 may be of relatively low power,e.g. up to 5 kw/m², but higher powers may be used when required. It willbe clear without further illustration that the control unit 60 can alsoregulate the operation of the heating elements.

The use of panels with heating elements is shown in the arrangement inFIG. 12, although tubular sheathed elements 103a are illustrated. Thisexample shows a further heat conservation measure, it being assumed inthis example that the arrangement is being employed with an existingsteel mill roller table, which will be equipped with large diameterrollers 110 of high thermal capacity, often water-cooled. The upper andlower thermal insulation panels 111, 112 have the general compositeconstruction already described and both series of panels are arranged inpairs side-by-side, with a central skid bar, 113 and 114 respectively,between the panels of each pair. The lower panels are also soconstructed that there are two or more successive panels along thedistance between adjacent rollers 110, and between these successivepanels transversely extending lifting bars 115 are interposed. Thesebars, of a high temperature alloy and possibly also provided with heatinsulation, can be raised e.g. by fluid pressure rams 116, to theposition shown and so lift the material 1 from the rollers 110. Themechanism can be used when the operation of the mill requires thematerial on the roller table to be stopped for any significant length oftime. Because of the thermal mass and/or the cooling of the rollers,there would be the risk that cold spots would develop in the material atthe regions of contact with the rollers, and that these would affect theuniformity of the final product.

The problem of avoiding undue heat loss to the rollers can alternativelybe overcome by modification of the roller table construction in themanner illustrated in FIGS. 13 and 14. The main supporting rollers 120have smaller rollers 121 resting on them, the rollers 121 being of aheat insulating material. Both series of rollers are journalled in ahousing assembly 122 and are driven together, as by the gearing 123. Itmay be arranged that the housing assembly can readily be opened toremove the rollers 121 at least, when servicing is needed. Upperheat-insulating panels 124 can be lifted clear in the manner alreadydescribed when this is to be done.

The main rollers preferably have reduced diameter portions 125 so thatthe contact area between the rollers 120, 121 is confined to therelatively small extent of the larger diameter portions 126, so reducingany heat loss through conduction. If scale drops from the material onthe table this measure also helps the scale to fall clear. It is afurther advantage in the use of the smaller diameter high-temperaturerollers that the lower heat-insulating panels 127 can be brought closertogether, so that there is a further reduction of heat loss byradiation.

Reference has already been made to the provision of means for raisingthe upper panels of a heat shield arrangement according to the inventionto prevent damage by lifting of the heated material or due to thematerial being deformed in such a way that its effective height isincreased. FIG. 15 illustrates an embodiment of a heat shieldarrangement incorporating a further example of such means, in thisinstance in the form of a self-contained module that can be fitted intoan existing rolling mill installation although its functional featuresare capable of wider application. The module comprises top, bottom andside panels 220, 222, 224 respectively supported on a rigid frame 226having mounting flanges 228. Elongated slots 230 formed in the sidemembers 232 of the frame to allow clearance for the mill roller-tablerollers (not shown). The bottom panels are mounted on cross-bracingsub-frames (not shown) which increase the stiffness of the frame 226.

Also mounted on the cross-bracing sub-frames are longitudinal bumper orfender bars 234 projecting above the bottom panels to protect them fromdamage by the hot strip. The bars also help to guide the leading edge ofthe strip from roller to roller, and when the arrangement is to formpart of the original equipment of a rolling mill installation theguidance offered by the bumper bars allows the roller table to bedesigned with the rollers to be spaced more widely apart than hashitherto been the practice so that there is a corresponding increase ofthe heat-insulating panel area.

The side panels are protected by bumper or fender elements in the formof upwardly extending bolsters 236 fixed rigidly to the main frame 226.The spacing between the bolsters will be determined by the anticipatedmeasure of sideways movement of the hot strip but generally two bolstersper side panel will be sufficient. In the design of the bolsters acompromise must be reached between mechanical strength and resistance tothermal stresses, as it will be appreciated that there will be largerthermal gradients within them. To minimise the generation of thermalstresses a series of slots or grooves 238 can be formed in the exposedor hot face of each bolster to allow the hot face to expand and contractrelatively freely. Thermal stress relieving grooves (not shown) maysimilarly be used in the hot faces of the bottom bumper bars and thefurther bumper bars 240 that are provided for the top panels.

Although supported through the rigid frame, the top panels 220 aremounted in a displaceable manner so that they can be lifted away fromthe roller table. As already mentioned this may be needed, for example,to prevent damage to the top panel if the hot strip lifts from theroller table but it is arranged that minor disturbances will not causethe top panels to lift and they are swung away from the roller tableonly if excessive upward forces occur on the bumper bars 240. Thus, ithas been found that the front end of a hot steel strip can often bouncefrom roller to roller as it is feeding through the roller table, and itwill then strike the bumper bars as it bounces, but not with any verygreat force. It is therefore an advantage to ensure that the heat shieldarrangement remains undisturbed by these relatively minor disturbances,although protective action is needed if excessively large upward forcesoccur.

In the preferred arrangement shown, the top panel bumper bars 40 aremounted separately from the top panels 220 themselves, on a carrierframe 242 mounted on pivot blocks 44 on the main frame 226, the blocksdefining a longitudinal pivot axis at the side of the roller table.Pairs of top panels are mounted each on a separate frame 46 that is alsoattached to the main frame and that surrounds the associated carrierframe 242. The panel mounting frames are pivoted on the samelongitudinal axis as the carrier frames and are capable of relativerotation thereto to a limited extent.

In the closed or operative position of the top panels, as shown by theforemost pair in FIG. 15, each bumper bar carrier frame 242 is held downwith a positive holding force by displacement means in the form of fluidpressure rams 248 and bears on adjustable stops 249 mounted on that sideof the frame 226 nearer the pivot axis. In the closed position the panelmounting frames are supported separately from the carrier frames, eachpanel mounting frame having a side flange 250 that can then rest uponthe fixed frame 226.

The hold-down force exerted by the rams 248 on the carrier frames willbe chosen in dependence upon the type of material being rolled, itstemperature, width and thickness. The arrangement is such that if thestrip strikes the bars 240 with a force less than the selected leveltheir carrier frame 242 remains in position, but if a higher force isexperienced the carrier frame will lift against the pre-loading forceand activate a limit switch 251 to switch the pressure connections tothe rams, so that the rams are extended and instead of holding down thebumper bars they lift the carrier frame 242. As the carrier frame risesit engages with brackets 252 the associated panel mounting frame and themounting frame, with the panels mounted on it, are then lifted togetherwith the carrier frame. To ensure positive entrainment of the panelmounting frame by the carrier frame in the downward closing movement,particularly if they are arranged to move to near to or past a verticalposition, brackets 253 secured to each carrier frame overlap a portionof its associated panel mounting frame.

In the fully lowered position of each carrier frame, a specificclearance is provided between the brackets 252 and the associated panelmounting frame by virtue of the independent support of the mountingframe on its side flange 250. In this way, while the carrier frame 242remains in its lower position, the impact loads on its bumper bars arenot transmitted to the panels or their mounting frame due to theindependent support arrangements of the carrier and support frames. Thebumper bars 240 therefore act as part of an independent cushioningsystem until a preset lifting force is experienced, so protecting thepanels until the disturbing force is so great that it displaces thebumper bars sufficiently to raise both carrier and mounting frames, andwith them the panels.

As an alternative or an addition to the limit switch already referred tofor triggering movement of the bumper bar carrier frame, an inertiaswitch 251a may be attached to the frame to switch the rams whenrequired. Since the inertia switch will respond in dependence upon themagnitude of the upwards force applied to the bumper bar, before the barhas been displaced significantly by the force, this can provide a morerapid response.

FIG. 16 shows an example of the control circuit that may be employed tooperate the rams in the manner already described. A pneumatic controlcircuit is shown but it will be appreciated that a correspondinghydraulic circuit could be employed for hydraulic rams or indeed anelectrical drive and control arrangement could be similarly substituted.

In the circuit shown, a compressed air supply 260 is fed through anelectrically operated isolation valve 262, a filter 264, a moisture trap266, a pressure regulator 268 and a pilot-operated diverter valve 270,to a manually controlled valve 272 having alternative open and closedpositions, the open position shown placing the circuit in its normaloperating state. Pressure air can pass through the open manual valve 72to a series of solenoid valves 274a, 274b and 276a and 276b whichcontrol the air flows to and from the rams. When the solenoid valves areenergised the rams are contracted to lower the top panels, but they areillustrated in their de-energised state, so that pressure air is feddirectly through lines 277 at full pressure to the underside of the rampistons to extend the rams 248 from the contracted state shown and raisethe panels rapidly while the ram cylinder spaces above the pistons areexhausted through lines 278 and the solenoid valves.

When the solenoid valves are energised and switched to the oppositepositions to those shown, if permitted by the state of pressure controlvalves 280, pressure air flows through the lines 278 to contract therams. Flow control valves 282 in the lines 278 and the lines 277 to theunderside of the ram pistons control the rate of contraction of the rams248 and therefore limit the speed at which the panels are lowered. Theyoperate only in this direction of flow and therefore do not limit thespeed of movement of the rams when the panels are being raised. Thepressure control valves 280 can be adjustably set, and by regulating thesupply pressure to the upper sides of the ram cylinders can determinethe preload that the rams apply to the upper bar support frame. It willbe understood from the foregoing description that the limit switchpreviously referred to controls the operation of the solenoid valves, sothat actuation of the limit switch changes the valves over from anormally energised state.

Spring loaded shuttle valves 286 are provided in the supply lines 277 tothe undersides of the rams and are shown in their normally biasedpositions. If required in an emergency, the solenoid valves can beoverridden by switching the manual valve 272 from the position shown.The main supply pressure is then applied to the shuttle valves to switchthem over and allow the pressure air to flow directly to the undersidesof the rams to lift the panels.

In the event of loss of main supply pressure, the pilot-operated valve270 automatically reverses to isolate the mains supply line and toconnect to the control circuit a back-up supply such as from acompressed air bottle 288. This back-up supply is fed through a furtherpilot-operated valve 290 which remains operative only if the back-upsupply is pressurised. If the back-up pressure falls the valve 290closes and with both pilot-operated valves then closed the controlcircuit is isolated.

The solenoid valves are energised from supply 291 and may be operatorcontrolled by means of electrical circuits from switches 294 mounted ona remote control panel to raise or lower the panels. Automatic overridesignals, initiated by switches such as the switches 251, 251a on thepanel bumper bars or their mountings, or from separate detector means(such as the detector 62 in FIG. 6) mounted unpstream of the heat shieldarrangement to be operated by bent or buckled stock entering the millroller table, can act on electromagnetic cut-out switches 298 to cut offthe electrical supply to the solenoid valves through the switches 294,thereby raising the panels. The cut-out switches 298 require to bere-set before the switches 294 become operative. Typically, the controlpanel will have a manual reset 300 for re-energising the automaticallyactuated cut-out switches to restore the electrical supply.Additionally, if the manual override valve 272 is switched to raise therams directly as already described, pressure air is then also fed to apneumatic or hydraulic switch 292 to isolate the electrical circuits andthereby de-energising the cut-out switches preventing remote control ofthe rams in this condition.

FIG. 15 shows the upper and lower panels at a uniform and relativelyclose vertical spacing, but this may not be possible at the entry regionof the heat shield arrangement. FIG. 17 shows a section through acontinuous rolling mill in which the material being rolled passescontinuously through roughing stands 302, along the roller table 304 tothe finishing stands 306. In this process it is not uncommon for thenose end of the slab or strip S to acquire a turn-up or set so that itis raised from the roller table to such an extent that it would not beable to enter the small spacing between the series of upper and lowerpanels 308, 310. To overcome this problem and to ensure that quite largeturn-ups can be accommodated, the arrangement has an entry regionprovided with guide means 312 that form an entry passage of increasedheight.

As FIG. 18 shows in more detail, the guide means comprise a robust baseframe 314 that is clamped to the side walls of the existing roller tableor is fixed rigidly to the mill foundations. Vertical members 316 of theframe support a transverse pivot bar 318 to which the leading end of anose entry guide member 320 is attached. The guide member can thus pivotwith the bar 318 but it normally rests upon adjustable bottom stops 322at its rear end. The guide member takes the form of a reinforced frameor plate structure and includes a central spar 34 that extends under themain bumper bar of the first upper panel of the heat shield arrangement.

In use, the guide member will normally remain in its illustratedposition under the combined action of its own weight and the hold-downforce that is being applied to the bumper bar. The entering sheetmaterial, if above the height of the bumper bar, will stroke the guidemember and be urged downwards to below the level of the bumper bar. Ifthe turn-up or deformation of the entering material is such as to beable to force the entry guide member upwards, this will also displaceits adjoining bumper bar and, as previously described, the panel raisingmechanism will be operated. On the other hand, since the entry membercan be of a very robust construction it is possible to arrange that itoffers considerable resistance to displacement and thereby partiallycorrects any turn-up of the entry material.

In other types of rolling mill the above-described entry guide means maynot be sufficient. For example, in semi-continuous mills the material isreduced from slab-form by consecutive passes backwards and forwardsthrough reversing roughing stands. In this process there areconsiderably greater variations in turn-up or lift of the material thanin a continuous rolling process and a much greater entry height must bepermitted. In that case, to employ entry guide means with little or noheat-insulating effect, as shown in FIGS. 3 and 4, may make it difficultor impossible to provide an effective heat shield arrangement and anarrangement such as is illustrated in FIG. 19 may be required.

In this arrangement, an increased height entry section 330 continuesover part of the extent of the heat-insulating panels themselves, andthis may occupy up to some 40% of the length of the roller table 304.The guide means 312 itself is generally similar to that alreadydescribed with reference to FIG. 18, but is of course disposed at ahigher level. As before it co-operates with the bumper bar associatedwith the leading upper panel 308a.

Where it is necessary to have a substantial vertical spacing between theupper and lower insulating panels, a further difficulty may arise, aswill now be explained with reference to FIG. 21 which shows in schematicform a part of a transverse cross-section of a hot strip S as on arolling mill delay table between mills, with heat shield panels 342, 344above and below the strip respectively. In the central part of its widthat portions such as P1 and P2 of the strip, most of the heat radiatedfrom the hot strip will effectively go to heat up portions ofcorresponding width of the heat shield panels. Some fall of temperaturewill result, to a similar extent for all such portions in the centralregion of the strip width.

At the edges of the strip, however, conditions are no longer uniform.Because a large proportion of the energy radiated from a marginalportion such as the edge width P3 will fall on parts of the heat shieldpanels which are beyond the width of the strip, this marginal portion ofthe strip gives up more heat to the panels so that there will be agreater fall in the temperature of the strip at its lateral margins.

This effect will be increased by heat loss to the sides between the topand bottom panels of the shield, where the energy radiated from thestrip over an angle α will be directly lost. The direct radiation losscan be reduced by increasing the width of the shield relative to thestrip, but then there is a greater energy loss from the hot strip toheat the marginal portions of the heat shield panels that will beparticularly marked during start-up.

FIG. 22 illustrates one form of hot strip rolling mill arrangementaccording to the invention in which in addition to upper and lowerheat-insulating panels 342, 344 heat-insulating side panels 346 aremounted at the outer edges of the upper and lower panels to form a heatshield surrounding the path of the hot strip S. It will be clear fromthe preceding explanation with reference to FIG. 21 that blocking offdirect leakage of radiant energy from the edges of the strip in thismanner will be advantageous under steady state conditions, but the sidepanels will themselves act as a heat sink when cold and the situationmay only be improved slightly during start-up conditions.

To overcome this problem, the side panels are provided with heatingmeans 348, which may be either contained within the panels, immediatelybehind an inner cover plate as illustrated, or be mounted over theinward face of the panels. In general it will be found that electricalheating elements provide the most convenient method of giving theflexibility of operation that is required, but other forms of heatingsuch as radiant tube gas or oil burners can be used.

Although not shown in detail in the drawings, each of theheat-insulating panels may comprise a thin-walled casing containing acore of one or more layers of heat insulating material.

Temperature sensors 350 are located at convenient intervals along thelength of the side panels 346 to monitor the inner surface temperatureand the sensor signals are utilised by a controller 352 and voltageregulator 354 to provide a stepped power input to the heating elementsof side panels for controlling the surface temperature.

In operation the apparatus may be controlled in the following manner.The desired side panel surface temperatures are first selected on thecontroller 352 and if the sensed values are below these temperatures thecontroller actuates the voltage regulator so that a controlled powersupply is fed to the heating elements. Instead of relying on voltageregulation the control may operate by on/off switching of the heatingelements. An interlock arrangement 356 prevents the heating of the sidepanels being switched on unless the finished stands R of the mill areready for production. Once steady state conditions are reached and thecontrol system switches off the side panel heaters, the panels of coursecontinue to function as part of a passive heat shield arrangement. Itwill be understood that in particular installations it may be requiredto also have heating means associated with the upper and/or lower panelsand these may then be operated in a similar manner.

It will be clear that the provision of such side heating means can be ofparticular advantage in the heat shield arrangement shown in FIG. 19,where there is a considerable distance between the upper and lowerpanels in the entry region of the roller table. As indicated by FIG. 20,therefore, the heating means as already described with reference to FIG.22 can be employed over the increased height entry region. It will beunderstood that the use of such side heating means can be employedelsewhere in heat shield arrangements according to the invention, andmay even be provided along the complete length of the heat shieldarrangement if required.

We claim:
 1. An arrangement for use with hot strip material beingprocessed in a hot-rolling mill, the arrangement comprisingheat-insulating panels, support means mounting said panels in respectiveseries above and below a path for said hot material through said mill,said panels each having a heat-insulating core and a cover plate formingan overlying main face for each of said panels, said cover plate facingsaid hot material and forming a hot face of said panel to radiate backheat from said hot material, said panels being operated with thetemperature of said cover plates close to that of the adjacent surfaceof said hot material, at least some of said panels being disposed withindividual panels side-by-side across the lateral extent of thearrangement, and adjustment means being connected to said individualpanels for adjustably displacing said panels in opposite lateraldirections relative to each other to vary their heat-insulating effecton a central region of said hot material relative to said effect onouter lateral margins of said hot material, and at least one array oftemperature sensors being laterally spaced across said material path foractuation of said adjustment means in order to selectively control thetemperature profile of said hot material in accordance withpredetermined values.
 2. An arrangement according to claim 1 whereinsaid adjustment means include means connected to at least some of saidpanels for displacing said panels laterally towards and away from eachother and for tilting said panels to displace their laterally outerregions towards and away from said hot material.
 3. An arrangementaccording to claim 1 wherein the adjustably displaceable panels aredisplaceable on said support means and said displacement means areconnected to said support means to displace said support means withtheir panels upwardly away from said material path.
 4. An arrangementaccording to claim 1 wherein said adjustably displaceable panelscomprise panels both of said series above the material path and saidseries below said path.
 5. An arrangement according to claim 1 whereinsaid panels comprise heating means for heating an adjacent region ofsaid hot material being processed.
 6. An arrangement according to claim5 wherein said array of temperature sensors also actuates said heatingmeans.
 7. An arrangement according to claim 1 comprising heat-insulatingpanels mounted adjacent opposite sides of said material path betweensaid upper and lower series of panels, and heating means carried by saidside panels for applying heat to lateral edge regions of said hotmaterial being processed.
 8. An arrangement according to claim 7 whereintemperature sensing means are disposed along the length of said sidepanels for controlling said heating means carried by said side panels.